Link belt



April 20, 1937. J. w. SHIELDS LINK BELT Filed June 23. 1933 @www #f INVENTOR fesse W. hield ATTO RNEYS Patented Apr. 20, 1937 2 UNITED STATES PATENT OFFICE LINK BELT Jesse W. Shields, Akron, Ohio, assignor to The Firestone Tire a Rubber Company, Akron,

hio. a corporation of 0hio Application June 23. 1933, Serial No. 677,216 8 Claims. (Cl. 305-10) This invention relates to link belts such as, for embodiment of the invention herein shown there example, the endless link belts constituting the are three rubber cushions 20, and they are vulpropelling means for certain kinds of tractors. canized to the spindle I I in spaced apart relation and more especially it relates to link belts havas shown in Figure 4. Said cushions normally ing pivotal connections comprising rubber beare of larger diameter than the inside diameter 5 tween adjacent links of the belt. of the sleeve I0, and in assembling the spindle The chief objects oi the invention are to prowith the sleeve, which is accomplished by forcing vide an improved pivotal connection of the charthe spindle axially thereinto, the cushions 2li are Y acter mentioned, for use with link belts; and to deformed by radial pressure so that they spread lil provide an improved link belt. More specifically, axially and fill the space between spindle and l0 the invention aims to provide an endless link belt sleeve. having rubber in its pivotal connections between 'Ihe force exerted by the deformed cushions links, which rubber will not be subject to as great 2l against the sleeve I9 assures frictional engage` torsional distortion as heretofore. Other objects ment between these parts sufficient to prevent l5 will be manifest. slippage during substantial relative angular 15 Oi' the accompanying drawing: movement between spindle I8 and sleeve I9, with Figure 1 is a fragmentary side elevation of a `the result that such relative angular movement tractor, anda link driving belt, embodying the imposes a torsional strain on the cushions 20. invention in its preferred form,mounted thereon; The lateral links I4 are so formed that their Figure 2 is a side elevation of two connected end portions overlap, as shown in Figure 3, when 20 links of the belt in normal angular relation they are assembled to form an endless belt. The Figure 3 is a section on the line 3-3 of Figleading ends of the links Il are designated I 4a ure 1; and the trailing ends thereof are designated Mb,

Figure 4 is an elevation of the spindle element the leading ends of the links beings outermost of a pivotal connection before it is assembled where said links overlap. The end portions of therewith; and the links are formed with suitable apertures to Figure 5 is a section similar to Figure 3, showreceive the pivotal connections that hold the links ing a, modied embodiment of the invention. in assembled relation. When the belt is assem- Referring to the drawing, I0 is one end portion bled, the trailing ends IIb of the links I4 engage ot the trame of a tractor, Il is a sprocket jourthe sleeves I8 of the pivotal connections, and the 30 naled therein, and I2 is a link belt or track for leading ends Ila of the links engage the spindles crawler type tractors, trained about said sprock- I 8 of said connecti0ns. The pivotal connections et, it being understood that the link belt is endhave a force lit with both the leading and trailing less and is trained about another sprocket (not ends of the links I4, so that pivotal movement of shown) similar to sprocket il, atleast one of the the links angularly with relation to each other 35 sprockets being power-driven. causes similar relative movement of the sleeves The belt I2 comprises a multiplicity of lateral I9 and spindles I8 of the pivotal connections, and links or members I 4, i4, said links being arranged imposes a torsional strain upon the cushions 2U. in two parallel series that are held in spaced The links Il are so assembled on the pivotal apart relation by connections that pivotally seconnections that adjacent links are disposed at 40 cure adjacent links of each series to each other, an angle to each other, as shown in Figure 2. said connections also being engaged by the teeth This angle may vary in different situations, but of sprockets upon which the belt is mounted. preferably itis approximately one-half the angu- Tresd plates I 5, each formed with a. projecting lar displacement which adjacent belt links underlug or cleat I6, are mounted upon the corrego in passing around the sprocket II, Figure 1. 45 sponding lateral link I4 of each series, said tread 'Ihus in passing around a sprocket, the cushions plates spanning the space between each series of 20 of the pivotal connections aresubjected only plates i4. to one-half the torsional strain they would other- As is clearly shown in Figure 3, the pivotal conwise normally be subjected to. In the straight nections between lateral links I4 of the belt each reaches of the belt between sprockets the adja.- 50 comprise a spindle I8, a sleeve I9 of somewhat cent belt links are in horizontal alignment, with shorter length and greater diameter concentric the result that the cushions 20 are placed under therewith and spaced therefrom, and one or more torsional strain that is of approximately the same cushions 20. 20 of resilient rubber composition extent as the strain imposed in passing around a between the spindle I8 and sleeve i9. In the sprooket,but in the opposite direction. 55

Thus when the limproved. belt is arranged in endless form and mounted ior use upon sprockets, the rubber in the pivotal connections of the belt links normally will be under torsional strains, which in some positions will be opposite in direction to what it is.in other positions. In all cases however, the maximum extent of deformation of the rubber will be but approximately onehalf of what it would be if the links were assembled in straight alignment and not at an angie to each other.

The feature of vulcanizing the rubber cushions 20 to spindles I8 and deforming the cushions by forcing them into a sleeve I9 oi smaller inside diameter than the diameter of the cushions is especially advantageous in that it lends itself to simple manufacturing methods as distinguished from methods requiring vulcanlzation of the rubber to the inner surface of the outer sleeve. Applicants construction also provides a relatively larger surface area for the frictional engagement of rubber and metal, so that there is rno slippage therebetween when spindle and sleeve move relatively of each other.

In the embodiment of the invention illustrated in Figure 5, the cushions 20 are vulcanized upon an inner sleeve A22, and inner sleeve 22 with the cushions 20 thereon is forced into outer sleeve I9. Spindle I8a is force-fitted into sleeve 22 during the assembly of the link belt. This type of connection is especially useful for joining the ends of a link belt to make it endless.

The invention makes for longer life of link belts for various uses in that the strains imposed on the rubber cushions of the pivotal connections are minimized. The invention also achieves the other advantages set out in the foregoing statement of objects. The invention has been specifically described in connection with a track construction for crawler type tractors. It will be understood, however, that the features of the invention may be employed in other relations where link belts are utilized.

Modi'ilcation may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. In a link belt the combination of a plurality of links, and pivotal connections between said links, each of said connections comprising an axial spindle, a sleeve circumscribing the same and spaced therefrom, and a bushing of rubber between said spindle and sleeve and having its inner portion vulcanized to said spindle and its outer portion frictionally secured to said sleeve and adapted to resist angular movement therebetween by torsion of the rubber, one end of each link being ixed to a spindle of a connection and the other end of the link being fixed to a sleeve of an adjacent connection, the adjacent links being disposed at a determinate angle to each other and the rubber bushings being free from torsional strain, said angle being such that the rubber bushing is putunder torsional strain in one direction in passing around a sprocket wheel and put under torsional strain in the opposite direction in the straight reaches of the belt between sprocket wheels.

2. In a link belt, the combination of a plurality of links, and pivotal connections between said links, each of said connections comprising a rubber bushing adapted to resist relative angular movement oi adjacent links by torsion of said rubber bushing, the adjacent links being disposed at a determinate angle with relation to each other and the rubber bushing being with- -.out torsional strain, said angle'belng greater than the angle between adjacent links as the latter pass around a sprocket wheel, and less than the angle between adjacent links in the straight reaches of the belt between sprocket wheels.

3. A combination as defined in claim 2 wherein the angular displacement from alignment of adjacent links is one-half the angular displacement from alignment of adjacent links passing about a sprocket wheel, whereby the rubber,- bushings are subjected to torsional strains alternately in opposite directions during use.

4. In a link belt the combination of a plurality of links, and pivotal connections between said links, each of said connections comprising an axial spindle, a sleeve circumscribing the spindle and spaced therefrom, and a bushing of rubber between said spindle and sleeve and having its inner portion vulcanized to said spindle and its outer portion frictionally secured to said sleeve, said rubber bushing at the time of vulcanlzation being of larger diameter than the inside diameter of said sleeve and being forced axially into said sleeve to place the rubber under constant radial compression, thereby resisting angular movement between the spindle and sleeve by torsion of the rubber, one endl of each link being i-lxed to a spindle of a connection and the other end of the link being fixed to a sleeve of an adjacent connection to thereby assure the imposition of torsional strains only upon the rubber during relative angular movement of the spindle and sleeve.

5. In a link belt the combination of a plurality oi links, and pivotal connections between said links, each of saidI connections comprising an axial spindle, a sleeve circumscribing the spindle and spaced therefrom, and a bushing of rubber between said spindle and sleeve and having its inner portion vulcanized to said spindle and its outer portion frictionally secured to said sleeve, said rubber bushing at the time of vulcanlzation being of larger diameter than the inside diameter of said sleeve and being forced axially into said sleeve to place the rubber under constant radial compression and axial tension, thereby resisting angular movement between the spindle and sleeve by torsion of the rubber, adjacent links being pivotally joined together to assure the imposition of torsional strains only upon the rubber during relative angular movement of the sleeve about the axis of the spindle, the adjacent links being assembled at a determinate angle to each other with the rubber bushings being free from torsional strain, said angle being such that, during travel of the belt, the rubber bushing is subjected to torsional strain in one direction when the belt passes around a sprocket wheel and in the opposite direction in the straight reaches of the belt between sprocket wheels.

6. In a link belt the combination of a plurality of links, and pivotal connections between said links, each of said connections comprising an axial spindle, a sleeve circumscribing the spindle and spaced therefrom, and a bushing of rubber between said spindle and sleeve and having its inner portion vulcanized to said spindle and its outer portion frictionally secured to said sleeve, said rubber bushing at the time of vulcanlzation being of larger diameter than the inside diameter of said sleeve and being forced axially into said sleeve to place the rubber under constant radial compression, thereby resisting angular movement amare? 3 A between the spindle and sleeve by torsion of the to each other with the rubber bushings being free rubber, one end oi each link being iixed to a from torsional strain, said angle being such that, spindle of a connection and the other end of the during travel of the belt, the rubber bushing is link being fixed to a sleeve of an adjacent consubjected. to torsional strain in one direction 5 nection to thereby assure the imposition of torwhen the belt around a sprocket wheel sional strains only upon the rubber during relaand in the,.opposite direction in the straight tive angular movement of the spindle, the adjareaches oi the belt between sprocket wheels. cent links being assembled at a determinate angle JESSE W. SHIELDS. 

